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Clifford Park Ph.D Dissertation.pdf (3.47 MB)

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Physical Properties of Oleocolloid and Hydro-Oleocolloid Matrices Made of Whey Protein and Oleogel

Park, Clifford
http://rave.ohiolink.edu/etdc/view?acc_num=osu1618592720965005

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Food Science and Technology.
In recent decades, the field of oil structuring has been extensively investigated to find alternatives to saturated and trans fats due to their negative health effects associated with the cardiovascular diseases. In particular, the field of oleogels (vegetable oils structured with gelators) has generated numerous classes of oleogels and documented that they are capable of not only mimicking texture of hardstock fats, but also delivering food protein. The objectives of this study were developing novel colloidal networks called oleocolloid (OC) and hydro-oleocolloid (HOC) made of whey protein [2.5, 5, or 7.5% w/w] and rice bran wax oleogels and characterizing their structural and textural properties mediated by the colloidal particle interactions and also the oleogelation process. Thermal analysis via differential scanning calorimetry (DSC) indicated that mechanical and thermal conditions required for OC and HOC sample preparation processes denatured whey protein. FTIR spectroscopy documented the extent of protein denaturation was different in oil (OC) and emulsion (HOC) where changes were more significant in the latter, documenting the effects of hydrophobicity on the protein structure and stability. However, the denaturation of protein did not affect the systems’ solid fat content (SFC) and polymorphic patterns of the oleogels. Instead, the presence of whey protein affected onset of melting in developed systems. The role of these colloidal interactions on the structural properties of OC and HOC systems was verified by polarized light microscopy and confocal microscopy analyses. Specifically, particle area of both protein and lipid networks in OC networks increased considerably as a function of increasing protein concentrations due to the particle-particle interactions. In contrast, that of protein and lipid networks in HOC networks were not only significantly smaller compared to OC systems, but also remained consistent regardless of protein content. The notably different structural properties between two major colloidal networks indicated the effects of colloidal interactions mediated by interactions between protein and oleogels and also the liquid medium type (oil vs. emulsion). Subsequently, the effects of these colloidal interactions on the mechanical properties of OC and HOC networks were evaluated by small and large deformation tests. Results clearly showed that the presence of protein and also its concentrations significantly influenced the viscoelastic properties including storage modulus (G′). Temperature sweep tests highlighted that the oleogelation profiles of OC and HOC systems differed due to different protein-lipid interactions in oil vs. emulsion. In addition, strain sweep tests showed that while OC displayed greater G′ with higher protein concentrations (0.07 ~ 0.38 MPa), that of HOC showed a decreasing pattern with increasing protein content (0.15 ~ 0.004 MPa). Similar observations were documented when OC and HOC systems were subject to large deformation through texture profile analysis. A fractional calculus-based model applied to creep-recovery tests confirmed that OC gels exhibited a greater gel strength than HOC gels. However, detailed analysis revealed that the latter displayed a greater extent of flexibility with a higher % recovery up to 10%. The observed discrepancy in the mechanical properties between OC and HOC networks was examined by fractal analysis using scaling theory equations. Results showed that OC was characterized as a weak-link regime where intermolecular protein or lipid interactions governed its macroscopic behavior. On the other hand, fractal dimensions acquired for HOC systems did not fit into neither strong nor weak-link regime due to complex structural formations from interactions among protein, water, and oleogels. The obtained findings signal that textural attributes of developed gel systems are largely influenced by the protein-lipid networks and that they may affect the final properties of food systems formulated with OC and HOC matrices.
Farnaz Maleky, Dr. (Advisor)
Rafael Jimenez-Flores, Dr. (Committee Member)
Campanella Osvaldo, Dr. (Committee Member)
Thomas Magliery, Dr. (Committee Member)
177 p.
Food Science

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Citations

  • Park, C. (2021). Physical Properties of Oleocolloid and Hydro-Oleocolloid Matrices Made of Whey Protein and Oleogel [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618592720965005

    APA Style (7th edition)

  • Park, Clifford. Physical Properties of Oleocolloid and Hydro-Oleocolloid Matrices Made of Whey Protein and Oleogel. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1618592720965005.

    MLA Style (8th edition)

  • Park, Clifford. "Physical Properties of Oleocolloid and Hydro-Oleocolloid Matrices Made of Whey Protein and Oleogel." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1618592720965005

    Chicago Manual of Style (17th edition)

osu1618592720965005
232
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